Field of the Invention
The present embodiments relate to a sound attenuating composite. More specifically, present embodiments relate to a lightweight sound attenuating composite comprising a sound attenuating material and EVA, recycled sound attenuating materials or constituents and/or a combination thereof.
Description of Related Art
Automobile manufacturers typically use sound attenuating materials to line various compartments of an automobile, such as the engine compartment, to inhibit noise from entering a cabin or interior portion of a vehicle. The sound attenuating material may also line the interior of the vehicle, such as the headliner and floorboard, to attenuating sound created from within the cabin.
Automobile manufacturers require the material to meet specific standards. For instance, the sound attenuating material must withstand certain temperatures without burning or melting. It is preferable that the sound attenuating material should not melt or burn, or if the material burns it should have a self-extinguishing characteristic.
Polyester, pure, virgin, or otherwise, is known in the art for use as a sound attenuating material and generally has good sound attenuating characteristics. However, it has been found that polyester does not perform well in the open flame test because the material burns and melts at high temperatures. Additionally, the polyester generally softens and sags at temperatures above 450 degrees Fahrenheit. In an attempt to improve performance of the sound absorbing material in the flame test as well as increase the sound attenuating characteristics, some portion of fiberglass was added to the polyester sound attenuating material. Although fiberglass performed better in the flame test and had good sound attenuation characteristics, it has a major drawback. Fiberglass may cause irritation to human skin, eyes and respiratory systems. Generally, the smaller the fiber sizes the harsher the irritation. Thus, although fiberglass is good in one respect it is not quite as appealing in others.
Another desire of auto-manufacturers and therefore providers is to increase fuel efficiency. This generally means at least attempting to reduce weight of vehicle parts. Still further, the need exists for maintaining or improving sound reduction which decreasing part weight. It is therefore desirable to improve acoustical performance while reducing weight or alternatively improve acoustical performance without increasing weight.
The information included in this Background section of the specification, including any references cited herein and any description or discussion thereof, is included for technical reference purposes only and is not to be regarded subject matter by which the scope of the invention is to be bound.